John McEnroe is a misunderstood guy, in sum an artist. This was actor Shia LaBeouf’s assessment of the tennis champ he portrays in Borg/McEnroe, tonight’s opening-night film at the Toronto International Film Festival. It focuses on the epic showdown between McEnroe and Swedish tennis master Bjorn Borg (Sverrir Gudnason) at Wimbledon in 1980.

Watching McEnroe play was akin to “Amadeus — he’s like the Mozart character,” said LaBeouf. A guy who didn’t process his genius, “he was just trying to win. Only after he got out of the tour did he have questions [about his process],” said the Transformers actor, who broke his foot practicing tennis during production. Gudnason and LaBeouf started practicing tennis six months prior to filming; neither had played the sport before. In addition, neither prepared for their roles by consulting with the giants they were playing.

“When he entered the game, it was a power sport,” said LaBeouf. “Borg brought touch and feel that wasn’t in the game. It wasn’t screaming rage. McEnroe used screaming rage as tactic, to manufacture his intensity to hype himself up. In that way, he’s an artist.”

LaBeouf noted that he wanted to work with the film’s Danish helmer, Janus Metz, because Armadillo, his documentary about Danish soldiers fighting in Afghanistan, was a big influence on the actors while they were filming Fury.

LaBeouf had read a version of another McEnroe script that “was a satire and wasn’t treating him with respect. He was sort of a screaming shrew.” The actor found Ronnie Sandahl’s Borg/McEnroe script “cathartic, but my first entrance [to the film] was Janus.”

Said Metz: “McEnroe tried to convince Borg to come to tennis [after he retired]. He was always missing Borg after that.”

Added LaBeouf: “Borg was his hero. For McEnroe, it was like going up against Superman and winning.”

Neon is releasing Borg/McEnroe stateside. Asked by a reporter why he doesn’t grant many interviews, LaBeouf said: “I do do interviews. I’m right here.”